To fix discolored clothes you can soak the discolored clothes in a tub of baking soda and water.
Soak the discolored clothes overnight in the baking soda and water mixture and the baking soda will help to whiten and fix the discolored clothes.
Soaking the clothes in some Oxiclean as well can help whiten and fix discolored clothes.
You can also sprinkle baking soda onto the discolored portion of the clothes and pour or spray some vinegar onto the baking soda.
Allow the baking soda and vinegar to work on the stained or discolored portion of the clothes and then scrub the clothes.
Then wash the clothes in a bleached based detergent or use a bit of bleach in the washing machine to wash the clothes.
Washing the clothes or soaking the discolored clothes in an enzyme based pre treatment solution.
Some clothes may not ever come completely back to normal if the discoloration has set in too long or is too severe but for most discolored clothes do come clean.